Carry a spare tube for those rare occasions when your tubeless tire cannot be plugged. A 4.00/4.50 x 19 inch FRONT TUBE can be used for the rear tire in an emergency, to get you home. A 19" tube installed in the rear wheel (17") lasts long enough to get you out of the woods, and being smaller, is easier to carry than a rear tube. A front tube fits in the rear easier than a rear tube fits in the front, making it the obvious choice to carry for emergency use. Besides it fits properly in 50% of the wheels on your motorcycle!

A small tube in the rear won't resist pinchflats very well but they last long enough, especially when it's only serving as a membrane for a tubeless tire.